Neurology 1 Flashcards
What part of the neurone receives inputs from other neurones and convey graded electrical signals passively to the soma?
Dendrites
What is the synthetic and metabolic centre of the nuerone?
Soma - integrates incoming signals that are conducted passively to the axon hillock
Where in a neurone is the site of initiation of the all or none action potential
Axon hillock and initial segment
What part of a neurone conducts output signals as actin potentials to other nuerones, mediates transport of materials between the soma and presynaptic terminal and vice versa?
Axon
What things exploit retrograde transport to infect neurones?
Several viruses
Give an example of a unipolar neurone?
Peripheral autonomic neurone
Give an example of a pseudounipolar neurone?
Dorsal root ganglion neurone
Give an example of a bipolar neurone?
Retinal bioplar neurone
Give an example of a multipolar neurone?
Lower motor neurone
What has a constant amplitude?
Action potentials
What does the distance over which current spread depend on?
Mmebrane resistance and axial resistance of the axoplasm
What provides myelin in the PNS?
Schwann cells
What provides myelin in the CNS?
Oligodendrocytes
What is the term given for when AP leap from one node of ranvier to the next?
Saltatory conduction in myelinated axons
What is the most common type of synapse?
Axodendritic
What two classifications do synapses fall into?
Inhibitory and excitatory
What is the transmitter in excitatory synapses?
Glutamate
What is the transmitter in inhibitory synapses?
Glycine. aminobutyric acid (GABA)
What transmitter activates cation ( positive) selective receptors?
Glutamate
What transmitter activates anion selective receptors?
Glycine, GABA
Name the three major amino acid neurotransmitters in the CNS?
Glutamate, GABA and glycine
What are released from synaptic esicles?`
Amino acids and amines
What are released from secretory vesicles?
Peptides
What do GABA and amines require to be synthesised by the neurones specifically?
Specific enzymes
What direction do K channels flow?
Outwards of cells (hyperpolarisation, inhibitory)
What shape are glutamate receptor channels?
Tetramers
What shape are GABA, glycine and nicorinic ACh gates channels?
Pentamers
What is the role of metabotropic glutamate receptors?
Modulation of neurotransmission (e.g. presynaptic inhibition (inhibition of Ca channels))
What channel is operated in ionotropic GABA a receptors?
Cl channels
What channel is operated in metabotropic GABA b receptors?
Potassium channel
Which is slower - ionotropic receptors or metabotropic (gprotein couples) receptors?
Metabotropic
Because the slow actions of metabotropic receptors (gprotein couples) cannot trigger APs - what do they do instead
Modulate synaptic actions
In relation to a graded potential - what can increase the amplitude and allow it to travel further?
Soidum
Give an example of a strategy to increase quantal (neurotransmitter) release - extensive innervation?
Purkinje cell - inferior olivary neuron synapse
In relation to the somatosensory system: what do low threshold units respond to?
Low intensity - non-damaging and non-painful stimli
In relation to the somatosensory system: what do high threshold units (nociceptors) respond to?
High (noxious, potentially damaging) stimuli